```python
import pandas as pd
import altair as alt
from vega_datasets import data
locations_table = pd.read_csv(r"https://raw.githubusercontent.com/SwanseaU-TTW/csc337_coursework1/master/pleiades-locations-latest.csv")
pd.set_option('display.max_columns', None)
alt.data_transformers.disable_max_rows()
locations_table.head()
countries = alt.topo_feature(data.world_110m.url, 'countries')
selector = alt.selection_single(empty='all', fields=['featureType'])
colours_condition = alt.condition(selector,'timePeriods:N',alt.value('#666666'))
scale= 1200
center= [-2,54]
clipExtent= [[0, 0], [400, 300]]
# Used world cropping map of India inspired from https://stackoverflow.com/questions/61135952/vega-lite-altair-how-to-center-or-crop-a-map-of-europe
background = alt.Chart(countries).mark_geoshape(
fill='#666666',
stroke='white',
).project(
type= 'mercator',
scale= scale, # Magnify
center= center, # [lon, lat]
clipExtent= clipExtent, # [[left, top], [right, bottom]]
).properties(
title='Europe (Mercator)',
)
scatter = alt.Chart(locations_table).mark_circle(
fillOpacity=0.6
).encode(
latitude='reprLat:Q',
longitude='reprLong:Q',
color=colours_condition,
tooltip=[ 'timePeriods', 'timePeriodsRange',"featureType:N"]
).project(
type= 'mercator',
scale= scale, # Magnify
center= center, # [lon, lat] 20,50
clipExtent= clipExtent, # [[left, top], [right, bottom]]
).properties(
title='Europe (Mercator)',
).add_selection(selector)
background + scatter
```